Escape mechanism for ships&#39; instruments and other precision instruments



June 2,

(3.. WALKER ESCAPE MECHANISM FOR SHIPS INSTRUMENTS AND OTHER PRECISION INSTRUMENTS Filed Jan. 25, 1925 -Patented June 2, 1925- UNITED STATES GEORGE WA LKER, OF NEWTON CENTER, MASSACHUSETTS.-

ESCAPE MECHANISM FOR SHIPS INSTRUMENTS AND OTHER, PRECISION INSTRUMENTS.

Application filed Ianuary 25, 1923. Serial No. 614,836.

To all whom it may concern."

Be it known that I, GEORGE WALKER, a citizen of the United States of America, and resident of Newton Center, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Essa e Mechanism for Ships Instruments an the following is a specification.

This invention relates to combined escapement and resettin stop devices for use in mechanism in' whlch the resetting must be effected with great, accuracy and .where there is appreciable weight and momentum to the parts reset. While the invention is particularly designed and intended for use in ships instruments of the type disclosed inmy copending application Ser. No. 319,392,, filed August 23, 1919, and Serial No. 614,338 filed 0 on evendate herewith, it is applicable to precision instruments in general.

Objects of the invention are 'to limit or control the speed of resetting thereby to restrain the mechanism against overthrow or rebound, to lock the mechanism in exactly the same position at each resetting, and in general to simplify and improve devices of the class described and renderthem more satisfactory in operation. I

For the purpose of illustrating the invention one concrete embodiment thereof is shown in the accompanying drawings, in which, I

Figs. 1 to 4 inclusive are front elevational views of.the escapement and stop mechanism in various ositions;

' Fig. 5 is a si e elevational view of the escapement and stop mechanism and parts associated therewith;

Fig. 6 is a, rear elevational view of the resetting mechanism taken substantially, on the line 6-6 of Fig. 5; and I Fig. 7 is a face' view of the dial and pointer.

The embodiment of the invention shown for the purpose of illustration comprises a shaft 8 upon the outer end of which is fas-- tened a pointer 9 adapted for movement,

around a dial 10. Shaft 8 is rotated by any suitable mechanism, not shown, and 1s arranged to be reset to a certain exact'position by an suitable resetting mechanism, such as coi spring 11 fast at one end at 12 to ther Precision Instruments, of which shaft 8 and fitting in a recess 13 in a housing 14 fast to back plate 15 adjacent the rear bearing of shaft 8. Means are preferably provided to prevent the tension of spring 11 from becoming excessive in case pointer 9 is rotated for a considerable period in a forward or clockwise direction, the latter 5 means may be in the form shown in Fig. 6, in which slots 16 are provided in housing 14 around the' periphery of the recess 13 to receive the hook end 17 of spring 11 which .snaps from one recess to the next when the tension of the spring exceeds 'a predeter mined'amount, or in other suitable form as for example that shown in Ser. No."614,837, filed on even date herewith.

To prevent shaft 8 from. being rotated withtoo great force by s ring 11 when the pointer is to be reset an thus disturb the adjustments of the device or cause breakage of parts, control or brake mechanism is pro- I vided in the form of an escapement device of the type disclosed in Figs. 1 to 4, comprising an escape wheel 18 fast to shaft 8 and an escape lever 19 having pallets 19' for alternate engagement with the teeth of the escape wheel, the lever being mounted for free swinging movement on post 20. Lever 19 has a tail 21 of sufiicient weight to regulate to the desired extent the resettingv speed of shaft 8.

The mechanism for stoppin pointer 9 35 at exactly the right position wien the de- 1 vice is reset comprises a stop 22 in the form of an arm or lever pivoted to a post 23 and extending'above and parallel to lever 19. Lever 19 carries a pin 24 which extends into a slot 25 in stop 22 to cause the two parts topswing in unison about their res ive' pivots. Stop. 22 is contacted by a pawl 26 pivoted at '27 to escape wheel 18 and .is adapted to be yieldingly retained in position to strike the free end of stop 22 by the provision, of a spring 28.. Pawl 26 may take the form ofa bell crank, one arm of which is'arranged to contact the hub 29'of escape wheel 18 to limit the outward throw of pawl 26 by the action of spring 28.

The tceiseration of the device is clearly illustra by Figs. 1 to 4. Fig. 1 shows the shaft in forward or clockwise rotation, arrow a' indicating the direction of rotation of P he l 1 ig- 2 sh s h p in forward movement with pawl 26 riding over the beveled end of stop 22. Fig. 3 shows the parts in reverse movement toward resetting position, arrow 2) indicating the direction of rotation of wheel 18. Fig. 4 shows the parts as the stop position is reached. As the end of pawl 26 contacts the free end of stop 22, it tends to move the latter to the right (Fig. 4) and to rock lever 19 so that its right-hand pallet 19 tends to swing upwardly, by reason of the interconnection of stop 22 with lever 19 by pin 24, into a notch in the toothed wheel as shown in Fig. 4. This upward pressure of the lever 19 to the right blocks the movement of escape wheel 18 and holds the end of the detent firmly between the teeth upon escape wheel 18 and pawl 26 and thus exactly fixes the stopping position for pointer 9, By reason of this interconnection of stop and lever, pointer 9 will be accurately positioned at the same point each time the device is reset. Any tendency to overthrow or rebound on the part of shaft 8 is suppressed by the constant pressure of spring 11 tending to turn escape wheel 18 in one direction and by the positive and definite locking of wheel 18 in the stop position. The arts are referably so interrelated that t e rightand pallet 19 is already in contact with the escape wheel when the pawl 26 engages stop 22, so that the engagement of the pawl and stop merely holds the pallet against the wheel. tion of spring 11 on stop 22 and pallet 19', the stop and pallet being interconnected, the wheel 1s stopped and held exactly in initial position by the stop and pallet. As shown in Fi 4 there is clearance between the ends of pa lets 19' and the teeth of the escapement wheel, only the inner faces of the pallets engaging the wheel.

I claim:

1. A device of the character described comprising an escape wheel adapted to be rotated in one direction, a spring for returning the wheel to initial position, an

escape lever for regulating the movement of.

the wheel, and mechanism for stopping the wheel in initial position upon the return movement, said mechanism including mutualljengaging parts associated with the wheel and lever respectively.

2. A device of the character described comprising an escape wheel adapted to be rotated in one direction, a spring for returning the wheel to initial position, an oscillatory escape lever having pallets for alternate engagement with the wheel to regulate the movementof the wheel in each direction, and mechanism for stopping the 'wheel in initial position upon the return movement, said mechanism including mutually engaging parts associated with the wheel and lever respectively to hold one of By virtue of the simultaneous acsaid pallets in engagement with the wheel when the wheel is returned to initial position.

3. A device of the character described comprising an escape wheel adapted to be rotated in one direction, a sprin for returning the wheel to initial position, an escape lever for regulating the movement of the wheel, and mechanism for sto ping the wheel in initial position upon t e return movement, said mechanism including mu; tually engaging parts associated with the wheel and lever respectively, one of the parts being pivotally mounted on said wheel.

4. A device of the character described comprising an escape wheel adapted to be rotated in one direction, a. sprin for returning the wheel to initial position, an oscillatory escape lever having pallets for alternate engagement with the wheel to regulate the movement of the wheel in each direction, and mechanism for sto ping the wheel in initial position upon the return movement, said mechanism including a member interconnected to said escape lever and a member on said escape wheel for engaging said member, to hold one of said pallets in engagement with the wheel when the wheel is returned to initial position.

5. A device of the character described comprising an escape wheel adapted to be rotated in one direction, a sprin for returning the wheel to initial position, an oscillatory escape lever having pallets for al'terna'te engagement with the wheel to regulate the movement of the wheel in each direction, and mechanism for sto ping the wheel in initial position upon t e return movement, said mechanism including a member pivotally mounted on the escape wheel arranged to ride over a sto interconnected to said escape lever w en the wheel is being advanced and to engage said stop to hold one of said pallets in engagement with the wheel when the wheel is returned to initial osition.

6. A device of t e character described comprising an escape wheel adapted to be rotated in one direction, a spring for returning the. wheel to initial position, an escape ever for regulating the movement of .ber mounted on the frame of the device.

7. A device, of the character described comprising an escape wheel adapted to be rotated in one direction, a spring for returning'the wheel to initial position, an-

escape lever for regulating the movement of the wheel, and mechanism for stopping the wheel in initial position upon the-return movement,- said mechanism including :1 initial position, the latter arm being adapt-- spring. pressed bell-crank pivoted on said ed to nde over said stop lever in the forwheel, one arm of which acts as a stop to ward movement of the wheel by virtue of 1 limit the action of the spring, and a stop said sprin o 5 lever interconnected to sald escape lever 'for Signed %y me at Boston, Massachusetts, engagement by the other arm of said bellthis 27th day of December, 1922. crank,to stop the wheel when returned to GEORGE WALKER. 

